docs: def _get_regional_term(self, C, imt, vs30, rrup):
          """
          Compute regional term for Japan. See page 1043
          """
          f3 = interpolate.interp1d(
              [150, 250, 350, 450, 600, 850, 1150, 2000],
              [C['a36'], C['a37'], C['a38'], C['a39'], C['a40'], C['a41'],
               C['a42'], C['a42']],
              kind='linear')
          return f3(vs30) + C['a29'] * rrup